Commitments and Contingencies (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Commitments and Contingencies
Legal Defense Reserve		$ 6,500
Limited partnership commitments
Commitments and Contingencies
Investment In Limited Partnership, Committed Amount	$ 145,000
Contributions to be made	54,516
Contribution made	$ 94,269

Represents the committed amount of investment in limited partnership made by the company.

No definition available.

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Namespace Prefix:	saft_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the amount of contribution made by the company to the limited partnership investment.

+ References

No definition available.

+ Details

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Namespace Prefix:	saft_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the amount of remaining committed capital due to be called.

+ References

No definition available.

+ Details

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Namespace Prefix:	saft_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
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Period Type:	duration

- Definition

Amount of loss contingency liability.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14326-108349

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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Namespace Prefix:
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Balance Type:
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